PURPOSE: To obtain particles of markedly fine sizes for electrophotographic toner, carriers for diagnostic reagent and the like by deposition polymerization of monomer components containing hydrophobic monomers in an aqueous system where particles of organic pigment are dispersed in the presence of a specific concentration of surfactant.
CONSTITUTION: In the presence of a surfactant such as sodium dodecylbenzenesulfate higher than the critical micelle conqentration(CMC), organic pigment particles such as those of pigment blue are dispersed in an aqueous medium to prepare a pigment dispersion. Then, the dispersion is diluted until the concentration becomes lower than CMC to give a dilute dispersion. The monomer component containing at least one of hydrophobic monomers such as styrene, at least one of hydrophilic monomes such as acrylic acid and a polymerization initiator are added to the dispersion to effect deposition polymerization to give the objective pigment-containing particles of markedly fine sizes, compared with the conventional pigments, thus the particles can be used as an electrophotographic toner and a carrier for supporting immunologically diagnostic reagent.
KAMIYAMA MIKIO
KOIZUMI YOSHIAKI
KIKUCHI TOMOE
Next Patent: BIAS CIRCUIT